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/* xscreensaver-systemd, Copyright (c) 2019 Martin Lucina <martin@lucina.net>
*
* ISC License
*
* Permission to use, copy, modify, and/or distribute this software
* for any purpose with or without fee is hereby granted, provided
* that the above copyright notice and this permission notice appear
* in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
* AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
* OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* This is a small utility providing systemd integration for XScreenSaver.
*
* When run from ~/.xsession or equivalent, this will:
*
* - Lock the screen before the system goes to sleep (using
* xscreensaver-command -suspend).
*
* - Ensure the XScreenSaver password dialog is shown after the system
* is resumed (using xscreensaver-command -deactivate).
*
* This is implemented using the recommended way to do these things
* nowadays, namely inhibitor locks. sd-bus is used for DBUS communication,
* so the only dependency is libsystemd (which you already have if you
* want this).
*
* https://github.com/mato/xscreensaver-systemd
*/
#include <assert.h>
#include <err.h>
#include <errno.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>
#include <systemd/sd-bus.h>
struct handler_ctx {
sd_bus *bus;
sd_bus_message *lock;
};
static struct handler_ctx global_ctx = { NULL, NULL };
static int handler(sd_bus_message *m, void *arg,
sd_bus_error *ret_error)
{
struct handler_ctx *ctx = arg;
int before_sleep;
int rc;
sd_bus_error error = SD_BUS_ERROR_NULL;
sd_bus_message *reply = NULL;
int fd;
rc = sd_bus_message_read(m, "b", &before_sleep);
if (rc < 0) {
warnx("Failed to read message: %s", strerror(-rc));
return 0;
}
/* Use the scheme described at
* https://www.freedesktop.org/wiki/Software/systemd/inhibit/
* under "Taking Delay Locks".
*/
if (before_sleep) {
rc = system("xscreensaver-command -suspend");
if (rc == -1) {
warnx("Failed to run xscreensaver-command");
}
else if (WEXITSTATUS(rc) != 0) {
warnx("xscreensaver-command failed with %d", WEXITSTATUS(rc));
}
if (ctx->lock) {
/*
* This will release the lock, since we hold the only ref to the
* message, and sd_bus_message_unref() will close the underlying
* fd.
*/
sd_bus_message_unref(ctx->lock);
ctx->lock = NULL;
}
else {
warnx("Warning: ctx->lock is NULL, this should not happen?");
}
}
else {
rc = system("xscreensaver-command -deactivate");
if (rc == -1) {
warnx("Failed to run xscreensaver-command");
}
else if (WEXITSTATUS(rc) != 0) {
warnx("xscreensaver-command exited with %d", WEXITSTATUS(rc));
}
rc = sd_bus_call_method(ctx->bus,
"org.freedesktop.login1",
"/org/freedesktop/login1",
"org.freedesktop.login1.Manager",
"Inhibit",
&error,
&reply,
"ssss",
"sleep",
"xscreensaver",
"lock screen on suspend",
"delay");
if (rc < 0) {
warnx("Failed to call Inhibit(): %s", error.message);
goto out;
}
/*
* Verify that the reply actually contains a lock fd.
*/
rc = sd_bus_message_read(reply, "h", &fd);
if (rc < 0) {
warnx("Failed to read message: %s", strerror(-rc));
goto out;
}
assert(fd >= 0);
ctx->lock = reply;
out:
sd_bus_error_free(&error);
}
return 0;
}
int main(int argc, char *argv[])
{
sd_bus *bus = NULL, *user_bus = NULL;
sd_bus_slot *slot = NULL;
struct handler_ctx *ctx = &global_ctx;
sd_bus_error error = SD_BUS_ERROR_NULL;
sd_bus_message *reply = NULL;
int rc;
int fd;
const char *match =
"type='signal',interface='org.freedesktop.login1.Manager'"
",member='PrepareForSleep'";
rc = sd_bus_open_user(&user_bus);
if (rc < 0) {
warnx("Failed to connect to user bus: %s", strerror(-rc));
goto out;
}
rc = sd_bus_request_name(user_bus, "org.jwz.XScreenSaver", 0);
if (rc < 0) {
warnx("Failed to acquire well-known name: %s", strerror(-rc));
warnx("Is another copy of xscreensaver-systemd running?");
goto out;
}
rc = sd_bus_open_system(&bus);
if (rc < 0) {
warnx("Failed to connect to system bus: %s", strerror(-rc));
goto out;
}
ctx->bus = bus;
rc = sd_bus_call_method(bus,
"org.freedesktop.login1",
"/org/freedesktop/login1",
"org.freedesktop.login1.Manager",
"Inhibit",
&error,
&reply,
"ssss",
"sleep",
"xscreensaver",
"lock screen on suspend",
"delay");
if (rc < 0) {
warnx("Failed to call Inhibit(): %s", error.message);
goto out;
}
/*
* Verify that the reply actually contains a lock fd.
*/
rc = sd_bus_message_read(reply, "h", &fd);
if (rc < 0) {
warnx("Failed to read message: %s", strerror(-rc));
goto out;
}
assert(fd >= 0);
ctx->lock = reply;
rc = sd_bus_add_match(bus, &slot, match, handler, &global_ctx);
if (rc < 0) {
warnx("Failed to add match: %s", strerror(-rc));
goto out;
}
for (;;) {
rc = sd_bus_process(bus, NULL);
if (rc < 0) {
warnx("Failed to process bus: %s", strerror(-rc));
goto out;
}
if (rc > 0)
/* we processed a request, try to process another one, right-away */
continue;
/* Wait for the next request to process */
rc = sd_bus_wait(bus, (uint64_t) -1);
if (rc < 0) {
warnx("Failed to wait on bus: %s", strerror(-rc));
goto out;
}
}
out:
if (reply)
sd_bus_message_unref(reply);
if (slot)
sd_bus_slot_unref(slot);
if (bus)
sd_bus_flush_close_unref(bus);
if (user_bus)
sd_bus_flush_close_unref(user_bus);
sd_bus_error_free(&error);
return EXIT_FAILURE;
}
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